import sys
import numpy as np
import numba  # noqa
from numba import njit, b1, i4, i8, f8  # noqa

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


def main(T):
    if T >= 30:
        return "Yes"
    else:
        return "No"


T = int(readline())

print(main(T)) import sys sys import numpy as np numpy import numba numba from numba import njit, b1, i4, i8, f8 read = sys.stdin.buffer.read read sys.stdin.buffer.read sys.stdin.buffer sys.stdin sys stdin buffer read readline = sys.stdin.buffer.readline readline sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline readlines = sys.stdin.buffer.readlines readlines sys.stdin.buffer.readlines sys.stdin.buffer sys.stdin sys stdin buffer readlines def main(T):
    if T >= 30:
        return "Yes"
    else:
        return "No" main if T >= 30:
        return "Yes"
    else:
        return "No" T >= 30 T 30 return "Yes" "Yes" return "No" "No" T T T = int(readline()) T int(readline()) int readline() readline print(main(T)) print main(T) main T readline = sys.stdin.buffer.readline sys.stdin.buffer.readline readline T = int(readline()) int(readline()) T readlines = sys.stdin.buffer.readlines sys.stdin.buffer.readlines readlines read = sys.stdin.buffer.read sys.stdin.buffer.read read def main(T):
    if T >= 30:
        return "Yes"
    else:
        return "No" def main(T):
    if T >= 30:
        return "Yes"
    else:
        return "No" main
import sys
import numpy as np
import numba  # noqa
from numba import njit, b1, i4, i8, f8  # noqa

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


def main(T):
    if T >= 30:
        return "Yes"
    else:
        return "No"


T = int(readline())

print(main(T))
